Save This hearty Thanksgiving Green Bean Casserole Pasta transforms the beloved holiday side into a satisfying main dish. The familiar flavors of creamy mushroom sauce, tender green beans, and crispy onion topping blend perfectly with al dente pasta for a comforting meal that works year-round.
I first created this recipe when looking for ways to use leftover green bean casserole ingredients after Thanksgiving. My family loved it so much that it quickly became a standalone favorite we enjoy throughout the fall and winter months.
Ingredients
- Pasta: Choose a short shape like penne or rigatoni that will catch the creamy sauce in its ridges and hold up well when baked
- Fresh green beans: Their bright flavor and texture are essential look for firm beans with vibrant color
- Cremini mushrooms: These add an earthy umami flavor that forms the backbone of this dish button mushrooms work too if preferred
- Yellow onion: Adds sweetness when cooked down properly dice uniformly for even cooking
- Garlic: Fresh minced cloves provide aromatic depth that dried simply cannot match
- Butter: Creates the base for your roux which thickens the sauce use unsalted to control salt levels
- Allpurpose flour: When combined with butter creates the roux that thickens your sauce without lumps
- Whole milk: Provides richness for the creamy sauce 2% works in a pinch but avoid skim
- Vegetable broth: Adds depth to the sauce while keeping the dish vegetarian use homemade for best flavor
- Parmesan cheese: Use freshly grated for best melting properties and flavor avoid the shelf stable variety
- Dried thyme: Adds subtle herbal notes that complement the mushrooms and green beans
- Nutmeg: A small amount enhances creamy sauces without being detectable always use freshly grated if possible
- Crispy fried onions: The essential topping that adds texture and nostalgic flavor Frenchs are classic but homemade are even better
Instructions
- Prepare Your Base:
- Boil pasta in generously salted water until just al dente about 2 minutes less than package directions. This undercooking is crucial as the pasta will continue to absorb moisture while baking. Add the green beans during the last 2 minutes which perfectly blanches them without overcooking. Drain thoroughly to prevent a watery casserole.
- Create The Flavor Foundation:
- Melt butter in a large skillet over medium heat until it begins to foam but not brown. Add diced onions and cook until translucent about 3 minutes stirring occasionally. The onions should become soft but not browned. Add sliced mushrooms and increase heat slightly cooking for 5 minutes until they release their moisture and begin to brown. This caramelization is critical for developing deep flavor. Add minced garlic and cook just until fragrant about 1 minute longer being careful not to burn it.
- Build The Sauce:
- Sprinkle flour evenly over the vegetable mixture creating a roux. Cook for 1 minute stirring constantly to eliminate raw flour taste. Gradually add milk and broth in a slow steady stream while whisking continuously to prevent lumps from forming. This gradual addition is the key to a smooth sauce. Bring to a gentle simmer and cook for 4 to 5 minutes until the sauce coats the back of a spoon. The sauce will thicken further when baked so dont worry if it seems slightly thin.
- Season And Combine:
- Remove pan from heat and stir in grated Parmesan thyme pepper salt and nutmeg until cheese melts completely. Taste the sauce and adjust seasonings remembering that the pasta will dilute the flavor slightly. Fold in the drained pasta and green beans using gentle motions to avoid breaking the pasta while ensuring even coating. The mixture should look glossy and well combined.
- Bake To Perfection:
- Transfer the mixture to a greased 9x13inch baking dish spreading evenly. Sprinkle crispy fried onions and optional cheddar cheese across the top ensuring complete coverage. Bake at 375°F for 20 to 25 minutes until the edges bubble and the top turns golden brown. For extra crispness broil for the final minute watching carefully to prevent burning.
Save The crispy onion topping is what makes this dish truly special. I learned through much trial and error that adding them just before baking rather than mixing into the sauce maintains their signature crunch. My grandmother always insisted on doubling the onion topping on her traditional green bean casserole, and I continue that tradition with this pasta version.
Make Ahead Options
This casserole is perfect for busy holiday planning. You can prepare the entire dish up to the baking stage, cover tightly with foil, and refrigerate for up to 24 hours. When ready to serve, remove from refrigerator 30 minutes before baking to take the chill off, then bake as directed, adding an extra 5-10 minutes to the cooking time. The crispy onion topping is best added just before baking rather than in advance to maintain maximum crunch.
Ingredient Substitutions
While traditional ingredients create that classic green bean casserole flavor, this recipe adapts beautifully to what you have on hand. Frozen green beans can replace fresh ones—just thaw and drain well before adding. Any short pasta works, including gluten-free varieties. For a lighter version, substitute half-and-half for whole milk. Cremini mushrooms can be swapped for shiitakes or portobellos for deeper flavor, or white button mushrooms for a milder taste. Fresh thyme makes a wonderful upgrade from dried—use 1½ teaspoons chopped fresh leaves.
Serving Suggestions
This versatile dish works beautifully as both a main course and a substantial side. For a complete vegetarian meal, serve alongside a simple arugula salad dressed with lemon vinaigrette. When serving as a side, pair with roasted turkey, glazed ham, or grilled chicken. For a full Thanksgiving-inspired meal any time of year, accompany with cranberry sauce and simple roasted vegetables. A glass of buttery Chardonnay or light Pinot Noir complements the creamy flavors perfectly.
Holiday Table Tips
Transform this casserole into a holiday showstopper with minimal effort. Transfer to a decorative oven-safe serving dish before adding toppings and baking. For an elegant presentation, sprinkle with fresh thyme leaves just before serving. Create individual portions by baking in ramekins, reducing cooking time to 15-18 minutes. For large gatherings, the recipe doubles easily—simply use two baking dishes rather than one oversized pan to ensure even cooking and maintain the perfect ratio of crispy topping to creamy interior.
Save I discovered that allowing the casserole to rest for a full 10 minutes after baking (rather than the suggested 5) makes serving much neater and allows the flavors to settle together beautifully. The first time I made this for my inlaws, my fatherin-law who claims to hate vegetables had three helpings and asked for the recipe. That's when I knew this dish was truly something special.
Recipe FAQ
- → Can a different type of pasta be used?
Yes, any short pasta like penne, rigatoni, or fusilli works well to hold the creamy sauce and toppings.
- → How can this be made dairy-free?
Use almond or oat milk and substitute vegan cheese for Parmesan and cheddar to enjoy a dairy-free version.
- → Is this dish suitable for meal prep?
Yes, assemble ahead and refrigerate. Bake before serving or reheat portions later for convenience.
- → What proteins can be added for a non-vegetarian option?
Shredded cooked turkey or chicken pairs perfectly for added heartiness and flavor.
- → How do I achieve a crispy topping?
Top generously with crispy fried onions and bake until bubbling and golden brown for best texture.